import java.util.Scanner;

public class Example09 {
    public static void main(String[] args) {
 //       int grade = 75; // 定义学生成绩
        Scanner scl = new Scanner(System.in);
        int grade = scl.nextInt();
        if (grade > 80){// 满足grade>80
            System.out.println("改成绩的等级为优");
        }else if (grade > 70){ // 不满足grade>80,但满足条件grade>70
            System.out.println("改成绩的等级为良");
        }else if (grade > 60){// 不满足grade>70,但满足条件grade>60
            System.out.println("改成绩的等级为中");
        }else {// 不满足grade>60
            System.out.println("改成绩的等级为差");
        }
    }
}
